Bollinger Band Support / Resistance [BBSR]

Summary:
This trading system script uses Bollinger Band indicators to generate trading signals whenever an underlying indicator touches the band.

Rules:
1. Buy Market - When the underlying indicator touces the lower band.
2. Sell Market - When the underlying indicator touches the upper band.
3. Sell Short Market - When the underlying indicator touches the upper band.
4. Buy To Cover Market - When the underlying indicator touches the lower band.

	 ' Assign the script parameters to script variables.
	_hitDistance = hitDistance
	_enableShorting = enableShorting
	_stopLoss = stopLoss
	_takeProfit = takeProfit
	_trailingStop = trailingStop
	_isPercent = isPercent

	 ' Use for holding the specified indicator keys, indexed by symbol index.
	Redefine _indicatorKeys(SymbolCount() - 1)
	 ' Use for holding the BBL indicator keys based on the specified indicator key, indexed by symbol index.
	Redefine _BBLKeys(SymbolCount() - 1)
	 ' Use for holding the BBU indicator keys based on the specified indicator key, indexed by symbol index.
	Redefine _BBUKeys(SymbolCount() - 1)
	 ' Iterate over all of the account symbols.
	For i As Integer = 0 To SymbolCount() - 1
		 ' Create an indicator for each account symbol, based on the specified indicator.
		_indicatorKeys(i) = IndicatorCopy(indicatorKey, i)
		 ' Create a BBL indicator for each account symbol, based on the specified indicator.
		_BBLKeys(i) = IndicatorBBL(_indicatorKeys(i) ,periods, factor)
		 ' Create a BBU indicator for each account symbol, based on the specified indicator.
		_BBUKeys(i) = IndicatorBBU(_indicatorKeys(i) ,periods, factor)
		 ' Add the indicators to the symbol chart.
		ChartIndicator(i, 0, C_INVISIBLE, _indicatorKeys(i),C_LINE, 1,0)
		ChartIndicator(i, 0, C_MERGE_RIGHT, _BBLKeys(i),C_LINE, 1,1)
		ChartIndicator(i, 0, C_MERGE_RIGHT, _BBUKeys(i),C_LINE, 1,1)
	Next

	 ' Get the indicator value for the specified symbol index.
	Define value As Number = IndicatorValue(_indicatorKeys(symbolIndex))
	 ' Get the BBL indicator value for the specified symbol index.
	Define BBL As Number = IndicatorValue(_BBLKeys(symbolIndex))
	 ' Get the BBU indicator value for the specified symbol index.
	Define BBU As Number = IndicatorValue(_BBUKeys(symbolIndex))
	
	 ' If the indicator value is near the lower band.
	If (BBL < value And value < BBL * (1 + _hitDistance)) Then
		 ' If a short position exists then generate a buy to cover order.
		If (_enableShorting And PositionExists(C_OPEN, symbolIndex, C_SHORT)) Then
			 ' Generate a buy to cover market order.
			BrokerMarket(C_BUY_TO_COVER,symbolIndex, 0, C_DAY, "Near lower band.")
		End If
		 ' If no long open positions exist.
		If (Not PositionExists(C_OPEN, symbolIndex, C_LONG))
			 ' Generate a buy market order.
			Define orderIndex As Number = BrokerMarket(C_BUY,symbolIndex, 0, C_DAY, "Near lower band.")
			 ' Set a stop loss on the order.
			BrokerSetStopLossPercent(orderIndex, _stopLoss, True)
			 ' Set a take profit on the order.
			BrokerSetTakeProfitPercent(orderIndex, _takeProfit, True)
			 ' Set a trailing stop loss on the order.
			BrokerSetTrailingStopLoss(orderIndex, _isPercent, _trailingStop)
		End If
	 ' If the indicator value is near the upper band.
	ElseIf (BBU * (1 - _hitDistance) <= value And value <= BBU) Then
		 ' If a long open position exists.
		If (PositionExists(C_OPEN, symbolIndex, C_LONG))
			 ' Generate a sell market order.
			BrokerMarket(C_SELL,symbolIndex, 0, C_DAY, "Near upper band.")
		End If
		 ' If no short open positions exist.
		If (_enableShorting And Not PositionExists(C_OPEN, symbolIndex, C_SHORT)) Then
			 ' Generate a sell short market order.
			Define orderIndex As Number = BrokerMarket(C_SELL_SHORT,symbolIndex, 0, C_DAY, "Near upper band.")
			 ' Set a stop loss on the order.
			BrokerSetStopLossPercent(orderIndex, _stopLoss, True)
			 ' Set a take profit on the order.
			BrokerSetTakeProfitPercent(orderIndex, _takeProfit, True)
			 ' Set a trailing stop loss on the order.
			BrokerSetTrailingStopLoss(orderIndex, _isPercent, _trailingStop)
		End If
	End If